Understanding Carbon Flows Between the Euphotic Zone and 1000 m depth

Texas A&M Research Foundation, College Station TX

Investigators

Abstract

The JGOFS program is designed to understand the biological and chemical processes that move carbon from the ocean's surface to it's interior and bottom. It's focus has been the euphotic zone, the region where carbon dioxide is reduced to organic carbon as part of the photosynthetic process. Data have been collected in the sub-euphotic zone, but there has been no concerted effort to relate the processes affecting carbon distributions there, either remineralization or fluxes to the benthos. For this project, the PIs will develop a more detailed understanding of carbon flows below the euphotic zone, incorporating the role of organisms into biological models. The model results will describe carbon flows between different groups of animals and bacteria. Preliminary models suggest that the timing and magnitude of seasonal productivity can dramatically affect the amount of material that passes through on its way to the ocean bottom. The study areas include the sites of the JGOFS field programs, starting with that of the North Atlantic Bloom Experiment. The focus on the 100 - 1000 m depth region is important because large amounts of organic matter enter as particles settling out of the euphotic zone, but only small amounts exit by falling through the bottom. The project results should stimulate further studies of the sub-euphotic zone by highlighting the important processes determining the fate of oceanic primary production as well as by exposing crucial areas of ignorance. The results also will help the development of better global models of the carbon cycle. This approach should be applicable to future JGOFS studies, particularly those concerned with the fate of organic matter.